The Boeing 737 had taken off from Moscow, and was reportedly trying to land but exploded on impact.
Russian officials told local media there were no survivors.
The plane belonged to Tatarstan Airlines, and crashed about 7:20pm local time (15:20 GMT) on Sunday, reports said.
The Emergencies Ministry said there were 44 passengers and six crew members on the flight.
There were no immediate indications of what may have led to the crash, but reports said the pilot had already tried to land twice before - and crashed on the third attempt.
The airport in Kazan - the capital of the Russian Republic of Tatarstan - has been closed since the accident.
The BBC's Daniel Sandford, in Moscow, says that although some of Russia's biggest airlines now have very good reputations, frequent crashes by smaller operators mean the country has one of the worst air safety records in the world.
-BBC
Follow @dailyprimekenya
